Inclosed safety switch



May 13, 1930. H. J. HAMMERLY INCLOSED SAFETY SWITCH Filed Oct. 19, 1928 3 Sheets-Sheet l Jrmml NVENTOR May 13, 1930. H. 1. HAMMERLY l INcLosED SAFETY SWITCH Filed Oct. 19, 1928 3 Sheets-Sheet 2 May 33, 1930. H. J. HAMMERLY 1,758,441

INCLOSED. SAFETY SWITCH Fled Oct. 19, 1928 5 SheeLs--Sl'uaetl 3 INVENTOR tetented Mey i3,

onirico stares iiitl PATNT @FHCE HERMAN J. if-XMMEBLY, 02? V"W.AIIL'ING-IEURD, CONNECTICUT, T0 T BULL ELEGTRIG M i'IUFeL/GTURING COMPANY, 011 PLNVLL,

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:ritenesse sannita swrrcn .Application filed october 19, 39%. Serial No. 813,550.

My invention relates particularly to that type ot' inclosed switches vvliicli employ replaceable fuses. The main object is to provide a simple but reliable interlocking mechanism which Will prevent access to the fuses when the switch is in the closed circuit or on position, but which vvill permit access to the fuses vvlien the switch is in the off position Without opening the main cover of the switch.

Another object is to provide an interlocking construction in which the parts vvillcooperate to automatically open the switch should an attempt loe made to close the switch box cover vvliile tlie shutter door is open and the switch is in closed circuit position and thus prevent a careless operator troni leaving the cover closed with the svvitcli in'closed circuit position and the slcnter door open and with the fuses exposed.

Another oloect is to VJprovide an interlocking construction which vvill 'nnction under the conditions ond in the manner specified in the preceding paragraph and in suoli a manner that tlie closing iinpact of the switch box cover will ioe cnsliioned by the resultant engagement and movement of the co-related ',oarts. A Another oloject is to provide interlocking, construction oit the oreinentioned character in which no injury to eny ot the co-related parts can 1ce consed the careless closing ot the sivitcii lion cover when the parts are in a relativel'7 nccrrect position.

Another soeciafi ject is to provide an interlocking n ecliani .rn oit the character described in .vliicli e of tire ports ere carried by sivitcli loo? r and soine are mounted in the loon 'o For i sivitcli loon is register normally closes tliis specilic cons nc'? 'on itself is not o nevertliel interlcc liable vf ich co with the t i' cre positiel for use in. connection iv" ose the cover oi? time led .vitli on opening end o shutter which Although the li ineciianisin nt invention, inplates en "tegole and recnlariy vvell nien the 'fuses gages the operating crank which entends back of the insulating base of tlie switch. A shoulder or hook portion at the outer end of the lever, stands in the patti ot movement ofi a part of the shutter or slide the switch is closed, so as to prevent the opening; nievement of the shutter when the switch' is in the closed circuit or on position.

The shutter and tire latch lever nre so constructed and co-related that, it tne tios cover is closed While the shutter is open and the switch is in the on position., the projection carried by the shutter 'will strike the latch lever and automaticeliy onen the switch..

The co-relation ot the svvitcliing parte, the latcliing, leverand the shutter is such that the closing impact of the cover is cushioned and, further, tliere is v.no possibility of injury 'to any oi tlie parte of the svvitcli or the interlocking ineinoers by the careless closing movement of the cover7 no ina-ttor what relative position the respective nir-,y occupy..

The svvitcli operating end latciiing mechaparte..

l is nerspective vie'iv ofi a construction einloodying" e improvements oit my inl I vention, tlie switch seing sliotvn in tire closed circuit position tine cover oe *ig snovvn onen and vitn the slide or shutter partly tli-e the 2 is transverse section snowing switch in the open circuit and cover ot tlie bon closed.

F 3 is a perspective vienr showing tlie bor; carts 'fleeing broken to show the interior with the switch operating and latching mechanism.

Fig. 4 is a longitudinal section showing' the switch closed and the'shutter latched so that it can not be opened.

Fig. 5 is a corresponding Isection showing the switch open and the shutter open.

Fig. 6 is a transverse section showing the parts of the switch in the closed circuit position and the action of the shutter a ainst the latching4 lever when the cover is eing closed.

The boX 5 with its cover 6 hinged for instance at 7, may be of any suitable construction preferably of sheet steel. The box is preferably provided with a spring catch 8 adapted to project through a slot 9 in the cover when the cover is closed and adapted to facilitate sealing or locking the box to prevent access to the circuit terminals.

The switch itself is preferably provided with an insulating base 10, supported on brackets 1l, which are suitably secured in the box. The particular switch illustrated, is intended for a three wire system. This, however, is immaterial to the present invention 1 and it will therefore be necessary to describe only a single unitof the switch which includes two stationary contact jaws 12 and 13. The connecting blade 14 carried by an insulating bar 15 has a number of actuating connector rods 16 which extend through guide plate-17 and are detachably connected with the switch operating crank 18 back of the base. This crank is provided with an external operating handle 19 of any suitable lli character. This switch mechanism is claimed in my copending application #310,089, iled Oct. 3,1928.

The switch is provided with suitable fuses such as 20 which are preferably enclosed laterally in a chamber formed by the insulating flange or receptacle 21. The cover is provided with an opening 22 which registers with the fuse chamber and this opening is provided with a slide or shutter 23 which is supported in guides 24 suitabl secured to the cover. The shutter is provi ed with a suitable 'handle or finger piece 25 for manually operating the same.

The latch lever 26 is pivoted at 27 near its center and supported by a plate 28 secured to an inner wall of the box. The inner end of Vthis lever is slotted at 29 to receive the switch operating crank 18. The outer end of the lever is provided with a shoulder or hooklike portion 30 adapted to stand in the path of movement of the projection 3l carried by the cover when the switch is closed and the cover is closed.

Preferably a spring 32 is connected to the lever 26 to hold it normally under tension so as to tend to move its outer end away from the cover. When the handle 19 is not restrained in the switch opening movement, this spring 32 causes the switch to open with a quick break movement.

When the parts are in the position shown in Fig. 3, that is, with the switch closed, the cover closed, and the shutter closed, it is impossible to open the shutter because the shoulder 30 stands directly in the path of movement or the upper end of the shutter projection 31. When-the switch is open, however, the lever 26 is tilted by the crank 18 so as to retract j the shoulder 30 from the path of movement of the shutter projection 31 and permit the shutter to be opened and thus permit access to the fuse chamber.

In the case the switch is closed while the cover is open and the shutter orslide is open,

the subsequent closing movement of the cover,

with the switch in this position, will cause the projection 31 to strike against the outer end of the lever 26 and tilt it and thus cause the slotted inner end 29 of the lever to co-act with the crank 18 and 'automatically open the switch. The spring 32 assists in this switch opening movement because of its tension on the lever and, provided the operating handle 19 is not restrained in the switch opening movement, this spring will cause a quick break movement ofthe switch blade 14 as soon as the blade has been freed from its comparatively tight contact with its co-operating stationary jaws 12 and 13.

For use in connection with certain types of switches, my present construction constitutes an important improvement over the Platt construction for a number of reasons. One is that it is better adapted to switches of the type in which the fuses are arranged above the switch blades.

It is also especially adapted to switch constructions in which the operatingcrank is positioned below or back 0f the base and it is applicable to such constructions regardless of the number of poles. The present construction is specially adapted to switches in which the line wires come into the bottom of the box and the load wires go out at the top .or sides. The present construction also particularly adapts itself for convenient manufacturing and assembling. The latch itself in this preferred form is a perfectly flat bar or plate which may be stamped out of strip sheet metal.

By the present construction I have also made it possible to prevent leaving the shutter open when the cover is closed and the switch is closed, as the closing of the cover, under these conditions, automatically opens the switch and thus calls the attention of the operator to his failure to close `the shutter as he should have done in order to house the fuses and thus properly protect the switch mechanism, the operator and the premises in ywhich the construction is installed.

A -feature of special importance is that no injury can be caused to any of the co-related llG iso

stand kin the path of movement of said shutter to latch said shutter closed when the switch is closed, means carried by the cover and adapted to engage and move said lever and said switch crank under abnormal conditions and a spring Vconnected to said lever for causing quick break movement of said switch. j

9. A safety switch including a box having a cover with an opening, a shutter i'or said opening, a projection carried by said shutter, a switch in said box, a switch operating crank, a lever having one of its ends connected with said crank and havinga shoulder at its other end adapted to stand in the path of movement of the shutter to keep the shutter closed when the switch is closed, said shutter having a portion adapted to engage said lever and move said switch operating crank to open the switch as the `cover is. closed when the switch is closed and `the shutter is in a certain position and a quick break spring for said switch connected toI said lever.

l0. A safety switch including a box having a switch operating crank, a lever having one end connected with said crank .and having a shoulder at the other end adapted to stand in the path of movement of the slide to keep the slide closed when the switch is closed and having a portion adapted to be engaged to move said lever and open the switch as the cover is closed with the slide in the open position.

ll. A safety switch including a box having av cover with an opening, a shutter for said opening, a projection carried by said shutter, a switch operating crank pivoted near the bottom of said box, and a lever pivoted near its center end having one end detachably connected with said crank andV having a shoulder at the other end adapted to stand in the path of movement of said shutter to prevent opening said shutter when the switch is closed and a spring connected to said lever for assisting in opening the switch and tending to hold said lever out of the path of movement of the shutter'. l

l2; A safety switch including a box having a cover with an opening, a. slide for said opening, a projection carried by said slide,

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a switch operating crank, a pivoted spring pressed lever having one end connected with said crank and having a shoulder at the other end adapted to stand in the path of movement of the yslide to prevent movement of the slide when the switch is closed and having a portion adapted to be engaged by the projection on said slide to move said lever and open the switch as the cover is closed when the switch islin closed circuit position and the slide is in a certain position, said spring mesa-.11'

tending to assist in the switch opening movement.

13. A safety switch including a box having a cover with an opening, a shutter for said opening carried by said cover, a projection carried by said shutter, a switch operating crank pivoted in said box and a lever having its inner end detachably connected with said crank and having a shoulder near its outer end adapted to stand in the path of movemen-t of said shutter to hold said shutter closed when the cover is closed and the switch is closed, said projection carried by the shutter being adapted to engage and cause a switch operating movement oi said lever if the cover is closed when the switch is closed and the shutter is not fully closed, and a spring connected to said lever for assisting in the opening of the switch.

la. A safety switch including a box having a cover with an opening, a shutter for said opening, a switch mounted in said box having protecting fuse devices exposed through said opening when said shutter is open, a switch operating crank and a lever having'one end detachably connected with said crank and having a shoulder at its other end adapted to stand in the path of movement of the shutter to keep the shutter closed when the cover is closed and the switch is closed, said shutter having a portion adapted to engage said lever and open the switch it' the cover is closed when the switch is closed and the fuse devices are exposed, and a spring 'connected to said lever to assist in opening the switch.

HERMAN J. HAMMERLY. 

